Self-stoking water heater



March 12, 1946. R. c. CROSS SELF-STOKING WATER HEATER Filed May 22, 19442 Sheets-Sheet 1 atzbaweg i March 12, 1946. R. c. CROSS SELF-STOKINGWATER HEATER Filed May 22, 1944 2 Sheets-Sheet 2 Mere/4 Patented Mar.12, 1946 SELF STOKING WATER HEATER Robert 0. Cross, Riverside, IIL,assignor to Sears, Roebuck and 00., Chicago',.lll., a corporation of NewYork Application May 22, 1944; Serial No. 536,707

(or. I22158) 6 Claims.

The present invention relates to domestic hot water heaters and isconcerned in particular with solid fuel burning heater constructiontherefor characterized by a self-stoking fuel supply feature.

In conventional coal burning domestic hot water heaters, fuel issupplied through a side door which leads directly to a combustionchamber, or is deposited downwardly from a top supply door, and theburning of the fuel is performed in the principal fire chamber with theresult that liberated products of combustion are wasted. Water jacketingwhich surrounds the combustion chamber is not always exposed so as tooperate as an efficient heat exchange medium because of its locationremote from the maximum heat concentrations.

In the present invention there is utilized a downwardly fed fuel supplconstruction in which the liberated gaseous combustibles which are freedas a result of the primary combustion process become exposed to asecondary oxygen supply in close proximity to the water jacketed partsof the boiler, so that during their combustion in which maximum heatliberation is achieved, these products are fully consumed as theliberated heat is directed in an enicient manner to the heat exchangewater jacketing which forms an outer enclosure of the principalstructure.

Accordingly, as its principal object the present invention contemplatesthe provision of a domestic hot water heater that is magazine fed in itsfuel supply and which directs its liberated combustibles resulting froma preliminar burning into a secondary stream of oxygen supply forcompletion of combustion thereof.

In the attainment of this and other objects the invention is illustratedin a principal embodiment consisting of a cylindrical heater dome thatis throughout water jacketed and is p'rovided with a central cylindricalcore forminga magazine hopper. This element lies directly'over arotatable circular grate provided with suitable openings for airadmission and ash disposal and provided with conventional oscillatingand agitating equipment.

The magazine hopper is preferably lined with refractory material and itslowermost extremity extendsjust beneath a cylindrical fire brick liningin which openings are provided to admit air for secondary oxygen supply;The magazine hopper is sealed by a hinged cover at its upper extremityand except for vent openings forms a closed chamber'forconfiningtth'erproductsof combustion that are induced in the? fuelsupply directing them downwardly and? outwardly beyond the refractorymaterial lining and into the stream of secondary oxygen supply. Anexhaust flue in communication with a circumferential chamber between thehopper and the heater dome draws the gaseous products of combustion asthe heat generated thereby is communicated to the heater dome andtherethrough to the jacket contained water.

For a more comprehensive understanding of the present invention,reference will now be had to the accompanying drawings and to thefollowing detailed specification, in which like numerical designationsidentify corresponding parts throughout, and in which:

Fig. 1 is a front elevation of a boiler construction having incorporatedtherein certain features of the present invention;

Fig. 2 is a plan View of the device illustrated in Fig. 1;

Fig. 3 isa vertical sectional view of the same device takenapproximately on line 3--3 of Fig. 2;

Fig. 4 is a plan sectional detail view taken approximately on line 4-4of Fig. 3 and featuring the construction of the circumferential firebrick wall; and

Fig. 5' is a detailed elevational view of one of the fire brick of whichseveral are used contiguously in forming the circumferential fire wallfeatured in Fig. 4.

Referring now more particularly'to the draw ings reference character lldesignates a base casting which provides an ash chamber l2 accessiblefrom one side through a pivoted ash door 83, Figs. 1 and 3, of customaryconstruction and a draft control door M through which the primary'supply of oxygen is obtained for supporting combustion of the fuel thatdescends upon the supporting grate IS;

The base casting H is substantially cylindrical in external conformationand affords a turret shoulder as at 1B with a supporting flange l! toreceive and confine a water-jacketed dome I 8. An opening is just abovethe ash clean-out door is admits the secondary oxygen supply into acircumferential distribution chamber 2|, see also Fig. 4, providedbetween the wall of the base casting l i that extends upwardly from thegrate sup porting ledge 22 and a cylindrical fire brick formationconsisting of the segmented brick elements 23 that may be cementedtogether and which are held spaced from the castingwall by reason oftheir specially provided spacer lugs 24 located at the tops and" bottomsof each brick extremity.

The base casting It rests upon three longitudinally extending feet 25and, in addition to a floor 26, this element is integrally formed withthe aforementioned ledge 22 that terminates with a concentric innerfiange 2? giving support to the ring casting 28 of the grate I 5. Thegrate is provided with a central opening defined by an inner concentricring 29 from which there extend the supporting lugs 3|, two on each sideof a shaker and draw center 32 that may be of conventional designincluding a handle 33 to be engaged by a convenience extension member(not shown).

Ledge 22 together with fire grate l divide the space within the basecasting H into a fire box or combustion chamber above and an ash chamberl2 below. The primary combustion takes place in the fire box and issupported by the principal source of oxygen admitted through the draftcontrol l4. The products of combustion, together with any partiallyconsumed gases are drawn around the skirt extremity 43 into the space 49about which more will be said later in connection with secondarycombustion thereat.

Each one of t e fire brick 23 is radially fluted as at 34. permittingthe admission of the secondary air in numerous small streams to thecombustion chamber 49, and the height of the brick coinc des with thedistance between the ledge 22 and the s oulder l6 so that the bottomwall of the jacket l8 rests upon said shoulder l6 and is contiguous withthe circular ledge formed b the array of brick 23.

The dome I8 is cast with an internal water jacketing chamber 35coextensive with the entire periphery of t e wall excepting t e flueopening 36 where a thimble 3! is formed for supporting the exhaust pipe38 through which the products of combustion are drawn off under impetusof the c imney draft a ter the conventional manner. The dome [8 includesa central cover sleeve 39 whose cylindrical inner surface conforms in 44is preferably beveled at 45 so that fuel may not rest upon the ledge,but instead wi l be directed downwardly into the internal chamber of thehopper.

The sheet metal hopper is also provided with a row of vent openings 46that communicate between the enclosed chamber of the hopper and a spacewhich surrounds the inner wall 41 of the dome I8 for the purpose ofcontinuousl removing by this direct draft passage, any gaseous productsof combustion that may accumulate above the fuel bed. At intervals in ahorizontal plane the inner wall 41 of the dome is provided with spacerlugs 48 that help to centralize the hopper by butting against thelowermost extremity of member 4i so as to assure the concentricity ofthe cylindrical space 49 which may be termed a combustion chamber aswill later be explained.

In order to make the apparatus universally adaptab e, the cast dome I8is provided with two riser bosses 5| and 52 and two return bosses 53 and54. For efficient operation one of the riser bosses 5i and 52 may beemnoyed with its diagonally opposite return boss 53 or 54 as illustratedin Fig. 1 and the domestic water pipe connections 55 and 56 threadedthereto while pipe plugs 51 may be employed to seal the unusedcommunication bosses according to individual requirements.

The magazine hopper is sealed at its upper end by a sheet metal circularcover 58 which may be engaged by a control handle 59 and pivoted aboutthe pivot stud 6i that extends through the cover hinge bracket 62 and apair of pivot yokes 63 integral with the dome casting I8, see Figs. 2and 3. The hinge 52 is cast with a stop lug projection 64 that isdesigned to rest against the dome as indicated in dotted outline in Fig,3 when the cover is open.

The cover58. is preferably a sheet metal hollow structure as has beensaid and is provided in its lower walls with bleeder openings 65 and inits upper wall with additional bleeder openings 65 that may be coveredby an adjustable ornamentation button 5'! slightly spaced therefrom sothat excessive gas accumulations of combustible material in the chamberof the hopper above the fuel bed may be supplied with an excess ofoxygen beyond an explosive mixture thus avoiding the occurrence of localexplosive effects in the maga zine.

The operation of the unit which has already been designated in a generalsense contemplates a supply of fuel contained within the hopper beneaththe cover '58 which is permitted to descend toward the grate 15 as it isconsumed and reduced to ash, affording a variable space within thehopper chamber complimentary to the fuel reserve therein contained.

The combustible gaseous products will follow generally the arrows 68circling the skirt of the refractory liner 43 and coming up into thecombustion chamber 49. Meanwhile, combustion supported by an air supplythat is admitted through the draft upon the opening of door l4 will burnthe fuel that is resting upon the grate E5. The gases, as has been said,will be drawn into the secondary chamber 49 taking on additional oxygenthrough the radial ports 34 and burning within the chamber 49 inproximit to the inner dome wall 4?. The products of combustion will bedrawn through the flue opening 35 into the exhaust pipe 38 and thenceout through conventional chimney escapeways, Accumulation of explosivegases above the fuel in the hopper is prevented by the vent openings 46so that upon the removal of the cover 58 to replenish the fuel reserve,no danger of local explosive effects may be incurred.

While the present invention has been explained and described withreference to a particular embodiment, it is to be understoodnevertheless that numerous variations and modifications may beincorporated without departing from the essential spirit or scopethereof. Accordingly it is not intended to be limited by the detailedillustrations in the accompanying drawings, nor by the specific languageemployed in the foregoing description, except as indicated in thehereunto appended claims.

The invention claimed is:

1. In a fuel burning boiler, a supporting base providing a fire box, acylindrical refractory wall carried by said base spaced from aconcentric cylindrical wall of said base and thus affording an airsupply avenue to a combustion chamber, a double walled casting forming awater jacket carried on said base and formed with a vertical collar, aconical hopper supported within said vertical collar defining saidcombustion chamber between itself and said casting, said hopper beingflared downwardly and extending into said fire box, and a pivoted coverfor said vertical collar and hopper carried bysaid casting.

2. In a boiler, a double walled dome casting forming a water jacket ofcylindrical conformation having a concentric vertical collar, a magazinehopper secured to said collar and extending downwardly into said dome inspaced relation to its cylindrical wall, a flue collar integral withsaid dome communicating with the space between said hopper and said domewall for connection with an exhaust pipe, a supporting base for saiddome comprising a cylindrical casting having a grate supporting ledge, agrate on said ledge defining an ash compartment and a fire box, aprimary air supply opening in said base for supporting combustion onsaid grate, a cylindrical refractory wall surrounding said fire boxhaving radial vents and spaced from the concentric wall of saidsupporting base for conducting a secondary air supply to the spacebetween said hopper and said dome casting.

3. In a fuel burning boiler, a double walled dome casting of cylindricalconformation forming a water jacket and having a vertical collar, atruncated conical magazine hopper secured to said collar and extendingdownwardly into said dome in spaced relation to its cylindrical wall, anexhaust flue collar integral with said dome communicating with the spacebetween said hopper and said dome wall, a supporting base casting forsaid dome having a grate supporting ledge, a grate defining an ashcompartment and a fire box, a primary air supply opening in said basecasting communicating with said ash compartment for supportingcombustion on said grate, and a secondary air opening in said basecasting in communication with said space.

4. In a water heating boiler, a dome casting comprising a cylindricalconformation of double walled wall structure forming a Water jacket,supply and return ports communicating with the intervening space betweenthe double walls of said casting, a conical fuel magazine supported inconcentric vertical alignment within said casting flaring downwardly inspaced relation to the cylindrical wall of said casting, a supportingbase for said casting horizontally partitioned to afford a fire boxbeneath said magazine, means for supplying a primary air supply tosupport combustion beneath said magazine, and means for supplying asecondary air supply to support combustion of volatile combustibles inthe space between said magazine and said cylindrical dome casting wall.

5. A water heating unit comprising a double walled dome casting forminga water-jacket, a refractory lined fuel hopper concentrically mounted insaid casting and spaced therefrom laterally to form a combustion chambercontiguous to the inner surfaces of said casting, a base comprising acylindrical wall section having an opening for admitting air to supportcombustion in said combustion chamber, a horizontal grate supportingshelf on said base, a grate on said shelf forming a primary combustionzone beneath said hopper and additional air supply means in said basefor supporting combustion in said pri mary zone.

6. In a hot Water boiler, a supporting base, an annular ledge interiorof said base, a fire grate supported on said ledge and partitioning saidbase into a fire box and an ash chamber, a cylindrical refractory wallsupported on said ledge and spaced from the base wall circumferentiallyto provide therebetween an air chamber, a double walled heater domewhich forms a water jacket nested on said base, a vertical collar onsaid dome, a sidewardly extending flue collar formed in said dome, aconical hopper suspended from said vertical collar having vent openingswhich connect the space within said hopper with the circumferentialspace between said dome and said hopper, said hopper being flareddownwardly and extending into said fire box of said base and having aninternal lining of refractory material, a cover for said vertical collarand hopper pivotally mounted on said dome, and pairs of threadedembossments integral with said dome and constituting feed and returncommunication ports with the water jacket of said dome.

ROBERT C. CROSS.

